Only allow node runtime in proxy (#85139)
This PR is the initiative of deprecating the edge runtime. Proxy will
default to Node.js runtime, and will not allow runtime config. If the
users want to use the edge runtime, they should stay on the Middleware,
though we recommend starting the migration.
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Co-authored-by: devjiwonchoi <devjiwonchoi@gmail.com>
Co-authored-by: JJ Kasper <jj@jjsweb.site>
